A low voltage relay is an electrically operated switch that uses a small control voltage (typically below 1000V AC or DC) to switch larger electrical loads on and off. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. Three fundamental components required for each circuit breaker. Types of Protective Relays: Protective relays are categorized by their mechanism (electromagnetic, static, mechanical) and function. Operating Principles and Relay Construction: Electromagnetic relays, thermal relays, static relays, microprocessor based protective relays Time-current characteristics, current setting, over current protective schemes, directional relay, protection of parallel feeders, protection of ring mains.
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